We plan to conduct immunocytochemical studies to localize fibronectin (FN) and collagen types I and III (Col I, Col III) in normal beagle periodontium and to determine changes in their distribution during ligature-induced and naturally-occurring periodontitis. We will measure FN, Col I, and Col III in gingival sulcular fluid and correlate these levels with inflammation as determined by light and electron microscopy and immunocytochemistry. Using the same methods, we will study the effect of inhibiting collagenase with minocycline on the level of FN, Col I, and Col III in gingival sulcular fluid. We expect to show that monitoring FN, Col I, and Col III in gingival crevicular fluid can be an accurate way to measure ongoing tissue destruction. If the beagle studies prove encouraging, we will begin similar investigations in humans. In a related project, we will use immunocytochemical methods to investigate the presence of FN in gingival plaque and calculus. We will continue autoradiographic studies of the penetration and incorporation into gingival epithelial cells of small metabolites applied to the gingival sulcular area. We hope to determine whether cell-to-cell communication and intracytoplasmic transport is a significant pathway in gingival epithelium. Preliminary findings suggest that further studies appear worthwhile. During the tenure of this grant, we have conducted numerous and basic studies of collagen secretion and fibroblast structure. We propose to continue these important studies by localizing fibroblasts rich in stress fibers by fluorescent microscopy with anti-actin and intermediate filaments with anti-vimentin antibodies. We will also examine the distribution of FN in relation to the development of fibronexus contacts by electron microscopy immunocytochemistry in areas previously identified by light microscopy to be sites rich in stress fiber development. We hope to correlate their presence with resistance to stress in the periodontal connective tissues. In vitro studies are also planned to further evaluate the polarity and locomotion of periodontal ligament fibroblasts in relation to the presence and distribution of stress fibers and fibronectin.